Clock



FIG. 1 is a perspective view of a clock showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof, wherein a left side view thereof is symmetrical to the right side view;

FIG. 5 is a plan view thereof; and,

FIG. 6 is a bottom view thereof. 

CLAIM The ornamental design for a clock, as shown and described. 